1. Field of the Invention
The present invention relates to the technology field of silver nanowires (AgNW), and more particularly to a transparent conductive film having AgNW-made metal mesh used for replacing traditional ITO transparent conductive substrate.
2. Description of the Prior Art
It is well known that touch panels are mainly applied in the electronic devices with small screen size such as smart phone and tablet PC. However, with the growing of demands made by market on All-in-One PCs, large-scale notebooks and displays with large-size touch panel, expensive manufacturing cost and high sheet resistance of the traditional ITO transparent conductive substrate have become the major problems of the large-size touch panel. As the person skilled in development and manufacture of the transparent conductive substrates knows, traditional ITO transparent conductive substrates exhibit an average sheet resistance of 100-400 ohm/sq.
Since the high sheet resistance of the transparent conductive substrate would cause the arithmetic speed of controlling and driving circuits in the large-size touch panel be pulled down, traditional ITO substrates are considered unsuitable for being applied in the production of the large-size touch panels. Accordingly, a touch panel having at least one metal mesh layer is developed and provided. FIG. 1 shows a schematic framework view of a conventional touch panel having metal mesh layer, wherein the touch panel 1′ comprises: a liquid crystal display (LCD) module 16′, a first optical adhesive 15′, a touch panel 10′, an upper electrode layer 101′, a lower electrode layer 102′, a second optical adhesive 11′, an anti-glare film 12′, a third optical adhesive 13′, and a cover lens 14′.
In the constitution of the touch panel 1′, nano wires 103′ for forming at least one metal mesh layer on the transparent substrate 100′ of the touch panel 10′ are silver nanowires (AgNW). The nano wires 103′ can be formed on the transparent substrate 100′ by treating an AgNW suspension (or dispersion) with a specific process of spin coating, rod coating, drop casting, or air spraying, and subsequently treating the AgNW coated onto the transparent substrate 100′ with a heat process such as annealing for enhancing the conductivity of the AgNW. However, resulted from the low thermal resistance of the AgNW, the high temperature (>200° C.) annealing process leads to an abrupt increase in the sheet resistance of the nano wires 103′ on the transparent substrate 100′ of the touch panel 10′.
So that, in view of the AgNW-made metal mesh of the conventional touch panel 10′ shows its primary drawback of low thermal resistance, inventors of the present application have made great efforts to make inventive research thereon and eventually developed a novel and inventive transparent conductive film